1. Field of the Invention
This invention relates to a plastic bag sealing device, particularly to one able to carry out multiple sealing at the same sealing location of a plastic bag to achieve a quick and firm sealing work, installed together with a dot-cutting device to cut a dotted line near the sealing location of the plastic bag and with an opening-cutting device to cut an opening for the plastic bag to comparatively downsize a work table of the sealing device, greatly elevating economic gain.
2. Description of the Prior Art
A conventional plastic bag-sealing machine, as shown in FIGS. 1 and 2, includes a worktable 10 provided thereon with a material intake press roller 11. A guide roller 12 is positioned beside the material intake press roller 11, a silicon rubber roller 13 is provided near the guide roller 12, and a material outlet guide roller 14 is disposed beside the silica gel roller 13. A sealing device 15 is positioned opposite to the silicon rubber roller 13 and provided with a rotating shaft 16 having a sealing blade 17 fixed thereon. Plastic bags 19 are wound to pass around the material intake press roller 11, the guide roller 12, the silicon rubber roller 13 and the material outlet guide roller 14 orderly to be conveyed forward, and the sealing blade 17 is rotated together with the rotating shaft 16. When the sealing blade 17 is rotated for one round and contacts with the silicon rubber roller 13, as shown in FIG. 2, it will perform sealing at the sealing portion 18 of a plastic bag 19. When the sealing blade 17 is rotated together with the rotating shaft 16 for a circle, the plastic bags 19 will be conveyed by the material outlet guide roller 14 for a distance that is exactly equivalent to the length of a plastic bag 19, and when rotated for a second round and contacting with the silicon rubber roller 13 again, the sealing blade 17 will carry out sealing for another plastic bag 19. Such incessantly circulating movement enables the sealing machine 1 to perform sealing automatically. However, in order to tightly seal a plastic bag 19, the conventional plastic bag sealing machine 1 has to reduce the conveying speed of the plastic bags 19 and the rotating speed of the sealing blade 17 to enable the sealing blade 17 to stay longer at the sealing portion 18 of a plastic bag 19 for insuring firmness of the sealed line of the plastic bag 19, thus reducing sealing speed and producing speed of plastic bags. In addition, due to being sealed only one time by the sealing blade 17, the sealed location of a plastic bag is insufficient in strength, likely to cause disqualified products; therefore, the conventional plastic bag-sealing machine 1 is only applicable to comparatively thin plastic bags 19. Moreover, the conventional plastic bag-sealing machine 1 has all its components transversely disposed in a line on the worktable 10, taking too much space.